1. Field of the Invention
The present invention relates to a traction elevator having a compensating rope guide, and more particularly to a traction elevator that can reduce the swing of the compensating rope so as to stop the emission of unpleasant noise and vibration of an elevator car, and thus increase the comfort of the ride in the car.
2. Description of the Related Art
FIG. 11(a) is a side view of an ordinary type of widely used traction elevator. In the traction elevator, three ropes 3 (only one is shown) are attached at a first end thereof to a top of a the car 1, and at a second end thereof to a top of a counterweight 2. The ropes 3 are guided by a deflector sheave 6a and a sheave 6 driven by a motor in a machine room 5 located over an elevator shaft 4. Friction between the ropes 3 and sheave 6 raises and lowers the car 1 in order to carry passengers and freight.
However, in a traction elevator operating in a very tall shaft, if there is an imbalance of weight between a portion of ropes 3 on the car 1 side of sheave 6 and a portion of the ropes 3 on the counterweight 2 side of sheave 6, the ropes 3 might slip on the sheave 6. Therefore, in the traction elevator operating in a tall shaft, as shown in FIG. 11(b), a compensating rope 7 is usually attached at a first end thereof to the bottom of the car 1, and at a second end thereof to the bottom of the counterweight 2.
Then, this kind of the compensating rope 7 can be roughly classified into three types.
First, as shown in FIG. 12(b), a wire rope 10 such as the rope 3 is used as the compensating rope 7. Second, as shown in FIG. 12(c), a chain 8 made of steel is in use as the compensating rope 7. Third, as shown in FIG. 12(a), a coated chain 13 composed of the chain 8 covered with coating 9 such as resin is also used as the compensating rope 7.
In the following description, the wire rope 10, the chain 8 and the coated chain 13 are referred to generically as the compensating rope 7.
As shown in FIG. 12(b), the wire rope 10 is generally used in a high-speed elevator, and a tension pulley 11 is usually attached at the curving portion of the wire rope 10 to tension the wire rope 10. Accordingly, the tension pulley 11 lowers the vibration of the wire rope 10 and puts the wire rope 10 in orbit.
The chain 8 is usually used in a relatively low-speed elevator. As shown in FIG. 12(c), this type of the chain 8 can omit the tension pulley 11 attached at the curving portion of the wire rope 10 in FIG. 12(b), and thus reduce the cost of equipment, because the chain 8 does not swing as easily as the wire rope 10 when hanging with the tension of its own weight.
However, if the chain 8 is used in a high-speed elevator, the chain 8 makes noise and swings more than the wire rope 10 in a condition of hanging with the tension of the weight of the tension pulley 11 in FIG. 12(b). Although the chain 8 does not swing as easily as the wire rope 10 when hanging with the tension of its own weight, the chain 8 is not available in the high-speed elevator.
In recent years, the coated chain 13 compromising the wire rope 10 and the chain 8 has been adopted.
As shown in FIG. 12(d), the coated chain 13 includes the chain 8 covered with the coating 9 that reduces noise. Further, guides composed of small rollers 14 are arranged above the curving portion of the coated chain 13 in order to reduce the swing of the coated chain 13. Therefore, the coated chain 13 can be adopted for a high-speed elevator.
However, as shown in FIG. 13, when a building with an elevator sways due to a sudden gust of wind or an earthquake, the coated chain 13 swings and then seems to shift over the rollers 14 at the downward side of the guides. On the other hand, at the upward side of the guides, the coated chain 13 is pulled by the car 1 or the counterweight 2 and goes up as it is. Accordingly, the coated chain 13 is strongly pressed against the rollers 14 and an angle bracket (not shown) supporting the rollers 14 at an acute angle, and then the coated chain 13 emits unpleasant noise due to resistance between the coated chain 13 and the rollers 14. Further, since the coated chain 13 is caught in a corner of the rollers 14, a rotation of the rollers 14 becomes difficult. As a result, the car 1 begins to vibrate, and the vibration may negatively influence the comfort of the ride in the car 1.
Accordingly, one object of this invention is to provide a traction elevator having a compensating rope guide which can reduce the swing of a compensating rope so as to stop the emission of unpleasant noise and vibration of an elevator car, and thus avoid negatively influencing the comfort of the ride in the car.
The object of this invention can be achieved by providing an elevator having a rope connected at the first end thereof to the top of a car and at the second end thereof to the top of a counterweight, and guided and driven by a sheave which is rotated by a motor, composed of a compensating rope suspended from the car to the counterweight, the compensating rope having a curving portion, a first linear portion on the car side of the curving portion and a second linear portion on the counterweight side of the curving portion for compensating an imbalance of weight between a portion of the rope on the car side of the sheave and a portion of the rope on the counterweight side of the sheave. A first guide is arranged to guide the first linear portion and the second linear portion. A second guide is arranged below the first guide and positioned between the extended lines of the first linear portion of the compensating rope and the second linear portion of the compensating rope for guiding the curving portion of the compensating rope. A frame is arranged in the pit of an elevator shaft for supporting the first guide and the second guide.